Per channel annotation with clear visual appearance

The Per channel annotation already developed in the dev version of the MNE, highlights the whole span of the data under view. This makes event localization visually too difficult.

What I have tried:

*I have changed the mne/viz/_figure.py code so that I could get the following annotation per channel:

The problem is scanning the window becomes too slow.
*

Is there anything that can be added to speed up the scanning of the data?